[Rust Client] several small fixes to code generation errors

[ahl]

This fixes a few rust code generation issues. I've included links to small test cases.

• compile errors incorrectly referencing types e.g. crate::models::crate::models::...
• compile errors on types named File
• compile errors on cyclic types
• compile warnings on incorrectly named enum values

Closes #8380

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  ./mvnw clean package 
  ./bin/generate-samples.sh
  ./bin/utils/export_docs_generators.sh
  

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
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• File the PR against the correct branch: master, 5.1.x, 6.0.x
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[ahl]

See these simple test cases:

• https://github.com/ahl/openapi-tests/blob/master/src/cycle_types.json
• https://github.com/ahl/openapi-tests/blob/master/src/enum_names.json
• https://github.com/ahl/openapi-tests/blob/master/src/file_type.json

Each includes the errors currently produced by master

[antifuchs]

This PR does get much further than the latest release in generating the client that I'm interested in (docspell's). Generating from the linked .yml file results in these cargo check errors:

    Checking openapi v1.0.0 (/Users/asf/Hacks/docspell-api-client/docspell-openapi)
error: named argument never used
   --> src/apis/item_multi_edit_api.rs:366:103
    |
366 |     let local_var_uri_str = format!("{}/sec/items/customfieldremove", configuration.base_path, itemId=crate::apis::urlencode(item_id));
    |                                     -------------------------------- formatting specifier missing     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ named argument never used

error[E0412]: cannot find type `ItemUploadMeta` in module `crate::models`
   --> src/apis/integration_endpoint_api.rs:106:128
    |
106 | ...ation, id: &str, meta: Option<crate::models::ItemUploadMeta>, file: Option<Vec<std::path::PathBuf>>) -> Result<crate::models::BasicRes...
    |                                                 ^^^^^^^^^^^^^^ not found in `crate::models`

error[E0412]: cannot find type `OneOfReferenceListOrganizationList` in module `crate::models`
  --> src/apis/organization_api.rs:55:143
   |
55 | ...on<&str>) -> Result<crate::models::OneOfReferenceListOrganizationList, Error<SecOrganizationGetError>> {
   |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in `crate::models`

error[E0412]: cannot find type `OneOfReferenceListPersonList` in module `crate::models`
  --> src/apis/person_api.rs:55:137
   |
55 | ...ption<&str>) -> Result<crate::models::OneOfReferenceListPersonList, Error<SecPersonGetError>> {
   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in `crate::models`

error[E0412]: cannot find type `ItemUploadMeta` in module `crate::models`
  --> src/apis/upload_api.rs:89:123
   |
89 | ...ation, id: &str, meta: Option<crate::models::ItemUploadMeta>, file: Option<Vec<std::path::PathBuf>>) -> Result<crate::models::BasicRes...
   |                                                 ^^^^^^^^^^^^^^ not found in `crate::models`

error[E0412]: cannot find type `ItemUploadMeta` in module `crate::models`
   --> src/apis/upload_api.rs:122:146
    |
122 | ..., item_id: &str, meta: Option<crate::models::ItemUploadMeta>, file: Option<Vec<std::path::PathBuf>>) -> Result<crate::models::BasicRes...
    |                                                 ^^^^^^^^^^^^^^ not found in `crate::models`

error[E0412]: cannot find type `ItemUploadMeta` in module `crate::models`
   --> src/apis/upload_api.rs:190:127
    |
190 | ..., item_id: &str, meta: Option<crate::models::ItemUploadMeta>, file: Option<Vec<std::path::PathBuf>>) -> Result<crate::models::BasicRes...
    |                                                 ^^^^^^^^^^^^^^ not found in `crate::models`

error[E0412]: cannot find type `ItemUploadMeta` in module `crate::models`
   --> src/apis/upload_api.rs:231:109
    |
231 | ...::Configuration, meta: Option<crate::models::ItemUploadMeta>, file: Option<Vec<std::path::PathBuf>>) -> Result<crate::models::BasicRes...
    |                                                 ^^^^^^^^^^^^^^ not found in `crate::models`

error[E0283]: type annotations needed
    --> src/apis/organization_api.rs:87:9
     |
87   |         serde_json::from_str(&local_var_content).map_err(Error::from)
     |         ^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the function `from_str`
     |
    ::: /Users/asf/.cargo/registry/src/github.com-1ecc6299db9ec823/serde_json-1.0.63/src/de.rs:2584:8
     |
2584 |     T: de::Deserialize<'a>,
     |        ------------------- required by this bound in `serde_json::from_str`
     |
     = note: cannot satisfy `_: Deserialize<'_>`
help: consider specifying the type arguments in the method call
     |
87   |         serde_json::from_str(&local_var_content).map_err::<F, O>(Error::from)
     |                                                         ^^^^^^^^
help: consider specifying the type arguments in the function call
     |
87   |         serde_json::from_str::<'a, T>(&local_var_content).map_err(Error::from)
     |                             ^^^^^^^^^

error[E0283]: type annotations needed
    --> src/apis/person_api.rs:87:9
     |
87   |         serde_json::from_str(&local_var_content).map_err(Error::from)
     |         ^^^^^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T` declared on the function `from_str`
     |
    ::: /Users/asf/.cargo/registry/src/github.com-1ecc6299db9ec823/serde_json-1.0.63/src/de.rs:2584:8
     |
2584 |     T: de::Deserialize<'a>,
     |        ------------------- required by this bound in `serde_json::from_str`
     |
     = note: cannot satisfy `_: Deserialize<'_>`
help: consider specifying the type arguments in the method call
     |
87   |         serde_json::from_str(&local_var_content).map_err::<F, O>(Error::from)
     |                                                         ^^^^^^^^
help: consider specifying the type arguments in the function call
     |
87   |         serde_json::from_str::<'a, T>(&local_var_content).map_err(Error::from)
     |                             ^^^^^^^^^

[wing328]

cc @frol (2017/07) @farcaller (2017/08) @richardwhiuk (2019/07) @paladinzh (2020/05)

[ahl]

Hey @wing328 -- how can I help to move this forward? Thanks.

[wing328]

@ahl did you see the issues reported by @antifuchs when he tried your PR/fix? Are you able to reproduce those locally?

[ahl]

@ahl did you see the issues reported by @antifuchs when he tried your PR/fix? Are you able to reproduce those locally?

Yes, he said "This PR does get much further than the latest release in generating the client that I'm interested in..." i.e. that it's a significant improvement over the latest version.

The Rust generator struggles with quite a few constructions--too many for me to fix in this PR. With over 2k open issues, it's a little hard to understand what's filed or not, but from the output @antifuchs posted I recognize several issues that exist independent of this PR:

• the ItemUploadMeta error is due to incorrect handling of multipart/form-data
• no support for oneOf schemas (hence the several
• general sloppiness and poor test coverage

[wing328]

Yes, he said "This PR does get much further than the latest release in generating the client that I'm interested in..." i.e. that it's a significant improvement over the latest version.

Totally agree on that. My question is wondering if you've looked into the issue he reported and the finding, and it's perfectly fine to have another PR to fix those instead of squeezing all the fixes into one giant PR.

no support for oneOf schemas (hence the several

We are definitely looking for contributors to help on that as we've already come up with the implementation in some other generators (java, csharp, go, python, and more). We can use these as the reference implementations to start with.

I'll take another look over the weekend and merge if no further feeddback/question from me.

Thanks again for the PR. Have a nice weekend.

[ahl]

Thanks, William. Yes I was able to reproduce those. I have some ideas about how to fix them, but this code feels quite fragile. I'm unsure about test coverage and wouldn't be confident that a fix in one place wouldn't regress another. In this PR I tried to stick to some pretty clear wins like resolving a fundamental issue with circular types.

[wing328]

@ahl when you've time, can you please elaborate on the problem ?

[ahl]

Yeah, sorry to leave that turd. This code section seems to be handling discriminators and relocates a particular variable into the discriminators variables. It previously did so destructively which caused the original variable to be absent.

This is definitely ugly and poorly structured, but I don't have a good sense of how it should be structured or how to properly and exhaustively test some of the subtle semantics here.

[wing328]

No worries bro. Do you have a spec that can reproduce the issue that you encountered with this line/section of code?

[ahl]

I was running the influxdb openapi spec through it: https://docs.influxdata.com/influxdb/v2.0/api/

[wing328]

OK. Will take a look when I can find the time later.

[wing328]

@antifuchs I wonder if you can open an issue with the details to track the problem you reported above. Thanks.

[wing328]

@thanks for the PR, which has been included in the v5.1.0 release: https://twitter.com/oas_generator/status/1373636654024380423